I am new to openmv. I am using openmv for below application which i need to detect the waterline in the picture.
could anyone tell me how i can do that? Thanks in advance.
Note:
1. the background may change all the time
2. and the water in tube is increasing,
3. i need to send out the signal(e.g. pull down some IO) when the openmv detect the waterline reach some point.
4. sometimes, foam exist in the tube if the water is not clean, and how can i detect the waterline in this case.

Color tracking is the easiest thing to do for this... however, it's very hard to do given you don't have much contrast in the scene...

How do you plan to mount the camera? Looking at the tubes from this direction? Can you possibly put some sort of background behind the tubes? And maybe color the water? Or color the tubes? It's hard to see the water line otherwise.

Color tracking is the easiest thing to do for this... however, it's very hard to do given you don't have much contrast in the scene...

How do you plan to mount the camera? Looking at the tubes from this direction? Can you possibly put some sort of background behind the tubes? And maybe color the water? Or color the tubes? It's hard to see the water line otherwise.

Thanks for the reply. I will start with color tacking.

Since it's still an idea, i don't have the integrated sample right now. Please see below picture for the tubes and camera position.
1. The background may change all the time because the cover is transparent, and i can't change the color of the cover.
2. In fact, the liquid is not the water, so the color is not fixed, but mostly it's colorless and transparent.
3. I will check if we can find the tube with color, and it may take time.

If you could put a colored float in the tubes it will be a lot easier to detect.

I can't add float in the tubes, the liquid in the tubes are different chemical reagents, the float may change its chemical composition. Thank you very much for the suggestion, it provides me a broader idea to solve this problem rather than just focusing the system itself.